PromiseKit：如何在ObjC中重试/轮询？

Question

PromiseKit "Common Patterns"文档在Swift中。

如何在Objective C中编写重试/轮询代码？

重试/轮询

<form (ngSubmit)="send()" #loginForm="ngForm">
    <div class="modal-header">
        <!-- code -->
    </div>
    <div class="modal-body">
        <!-- code -->        
    </div>
    <div class="modal-footer">
        <!-- code -->
        <button class="btn btn-primary btn-lg btn-primary-light-blue" type="submit" (click)="send()">Valider la modification</button>
    </div>
</form>

Answer 1

由PromiseKit开发人员在Github上回答：

- (AnyPromise *) attempt:(NSUInteger) maximumRetryCount delayBeforeRetry:(NSTimeInterval) delay provider:(AnyPromise* (^)()) provide {
    __block NSUInteger attempts = 0;
    AnyPromise *(^attempt)() = ^{
        attempts++;
        return provide().catch(^(id error) {
            if (attempts >= maximumRetryCount) @throw error;
            return PMKAfter(delay).then(attempt);
        });
    };
    return attempt();
}

然后，如果您有这样的方法：

- (AnyPromise *) myPromise {
    return [AnyPromise promiseWithResolverBlock:^(PMKResolver resolve) {
        ...
        resolve(nil) / resolve (error); 
    }];
}

致电

[self attempt:3 delayBeforeRetry:2 provider:^{ return [self myPromise]; }]